title: Plasma arginine-vasotocin and hydroosmotic status of the terrestrial pit viper Bothrops jararaca.
abstract: Peaks corresponding to arg-vasotocin obtained by HPLC from Sep-Pak C18 column extracts of Bothrops jararaca plasma were identified by radioimmunoassay and amino acid analysis. Plasma vasotocin and protein levels, osmolality, and L-cystine-di-beta-naphthylamidase were also compared in snakes under normal hydration conditions with or without chronic administration of vasotocin or in the presence of chronic hydroosmotic challenges. Sep-Pak C18 and radioimmunoassay were validated for the extraction and determination of this peptide, respectively (about 80% recovery). EDTA presented a protective action on this recovery compared to the use of heparin as anticoagulant for snake blood. A reduction of vasotocin content related to the time of incubation of this peptide added to snake plasma was detected by radioimmunoassay. Snake plasma activity also on L-cystine-di-beta-naphthylamide indicated that this vasotocin-destroying effect was due to hydrolysis by a cystine-aminopeptidase-like activity. Plasma levels of vasotocin revealed an unexpected dispersion and absent correlation with plasma levels of osmolality. Measurable vasotocin in a large number of snakes associated with lower levels of l-cystine-di-beta-naphthylamidase in acute than in chronic salt loading suggested the role of this enzyme activity in long-term regulation of the vasotocin system in this snake.
authors.affiliation: Department of Physiology, Instituto de Biociências, São Paulo, 05503-900, Brazil.
authors.forename: P F
authors.initials: PF
authors.lastname: Silveira
authors.forename: T I
authors.initials: TI
authors.lastname: Koike
authors.forename: L N
authors.initials: LN
authors.lastname: Schiripa
authors.forename: A P
authors.initials: AP
authors.lastname: Reichl
authors.forename: F C
authors.initials: FC
authors.lastname: Magnoli
authors.forename: O M
authors.initials: OM
authors.lastname: Mimura
mesh_terms: D000596:Amino Acids / Q000097:blood; D000626:Aminopeptidases / Q000097:blood; D000818:Animals; D017837:Bothrops / Q000097:blood* / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D003553:Cystine / Q000097:blood; D005260:Female; D005508:Food Deprivation; D006868:Hydrolysis; D008297:Male; D009994:Osmolar Concentration; D011863:Radioimmunoassay; D012727:Sex Characteristics; D012965:Sodium Chloride / Q000008:administration & dosage; D014668:Vasotocin / Q000097:blood*; D014867:Water / Q000378:metabolism*; D014868:Water Deprivation
chemical_list: D000596:Amino Acids; D014867:Water; D012965:Sodium Chloride; D003553:Cystine; D000626:Aminopeptidases; D014668:Vasotocin